Isolation, formulation and shaping of macrocyclic oligoesters

ABSTRACT

Processes for isolating, formulating, and shaping macrocyclic oligesters were developed which allow efficient production of macrocyclic oligoesters substantially free from solvent, which may include additives, fillers, and catalysts.

RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.Provisional Application Ser. No. 60/301,399, filed on Jun. 27, 2001,entitled “Melt Isolation, Solidification, and Formulation of MacrocyclicOligoesters,” which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

The invention relates generally to thermoplastics and articles formedtherefrom. More particularly, the invention relates to processes forisolating, formulating, and shaping macrocyclic oligoesters such asmacrocyclic oligoesters of 1,4-butylene terephthalate.

BACKGROUND INFORMATION

Linear polyesters such as poly(alkylene terephthalate) are generallyknown and commercially available where the alkylene typically has 2 to 8carbon atoms. Linear polyesters have many valuable characteristicsincluding strength, toughness, high gloss, and solvent resistance.Linear polyesters are conventionally prepared by the reaction of a diolwith a dicarboxylic acid or its functional derivative, typically adiacid halide or ester. Linear polyesters may be fabricated intoarticles of manufacture by a number of known techniques includingextrusion, compression molding, and injection molding.

Recently, macrocyclic oligoesters were developed that have uniqueproperties that make them attractive for a variety of applications,including as matrices for engineering thermoplastic composites.Macrocyclic oligoesters exhibit low melt viscosity, for example,allowing them easily to impregnate a dense fibrous preform followed bypolymerization to polymers. Furthermore, certain macrocyclic oligoestersmelt and polymerize at temperatures well below the melting point of theresulting polymer. Upon melting and in the presence of an appropriatecatalyst, polymerization and crystallization can occur virtuallyisothermally.

Production of macrocyclic oligoesters such as macrocyclic (1,4-butyleneterephthalate) typically involves the use of one or more solvents suchas o-dichlorobenzene or xylene. Some prior techniques that have beenused to recover macrocyclic oligoesters dissolved in a solvent requiredthe addition of a large amount of anti-solvent to the solution toprecipitate the macrocyclic oligoester followed by collection of theproduct using a filter or a centrifuge. The use of anti-solvents resultsin increased processing complexity, costs, and creates additionalenvironmental storage and disposal concerns.

Linear polyesters may be depolymerized to form macrocyclic oligoesters.The product solution of a depolymerization reaction may be dilute,making recovery more time consuming. Depolymerization production effortsalso generally take place in stages, with each stage including a step ofthe process and with intermediate storage between the steps.

SUMMARY OF THE INVENTION

There is a need for effective, efficient, and low cost processes forisolating, formulating, and shaping macrocyclic oligoesters. There isalso a need for processes that enable continuous production ofmacrocyclic oligoesters. In one aspect, the invention generally relatesto processes for producing macrocyclic oligoesters (e.g., macrocyclic1,4-butylene terephthalate oligomers), including processes for isolatingmacrocyclic oligoesters from solvents so the resulting macrocyclicoligoesters are substantially free from solvent. The invention alsoincludes processes for formulating and shaping the substantially solventfree macrocyclic oligoesters. In some embodiments, the describedprocesses are performed continuously, to enable continuous production ina manufacturing plant. Further, the described processes can bebeneficially combined for greater efficiencies and production benefits.

In one aspect, the invention features a process for isolating amacrocyclic oligoester. A solution including a macrocyclic oligoesterand a solvent is provided. The macrocyclic oligoester typically has astructural repeat unit of formula (I):

where R may be an alkylene, a cycloalkylene, or a mono- orpolyoxyalkylene group, and A may be a divalent aromatic or alicyclicgroup. The solvent is then removed without the use of anti-solvent. Intypical practice, substantially all of the solvent is removed. In oneembodiment, the solvent is removed under elevated temperatureconditions. In another embodiment, the solvent is removed under reducedpressure conditions. In another embodiment, the solvent is removed undera combination of both elevated temperature and reduced pressureconditions. The macrocyclic oligoester, which is substantially free fromthe solvent then typically is collected. In one embodiment, the solventis continuously removed from the solution. In another embodiment, themacrocyclic oligoester substantially free from the solvent iscontinuously collected.

In another aspect, the invention features a process for shaping apartially-crystallized macrocyclic oligoester. In one embodiment, thisprocess includes providing a substantially solvent-free moltenmacrocyclic oligoester typically having the structural repeat unit ofthe formula (I) described above. The substantially solvent-free moltenmacrocyclic oligoester is sheared to form a partially-crystallizedmacrocyclic oligoester. The partially-crystallized macrocyclicoligoester is then shaped. In one embodiment, a continuous flow ofsubstantially solvent-free molten macrocyclic oligoester is shearedcontinuously. In another embodiment, the step of shaping thepartially-crystallized macrocyclic oligoester is conducted continuously.

In yet another aspect, the invention features a process for making aprepreg of a macrocyclic oligoester and a polymerization catalyst. Inone embodiment, a mixture of a molten macrocyclic oligoester and apolymerization catalyst, which is substantially free from any solvent,is provided. The macrocyclic oligoester typically has the structuralrepeat unit of the formula (I) described above. The mixture is depositedonto a fabric material, forming a prepreg. In one embodiment, themixture is partially-crystallized prior to being deposited onto thefabric material.

In yet another aspect, the invention features a process for making aprepreg of a macrocyclic oligoester and a polymerization catalyst. Inone embodiment, a mixture of a molten macrocyclic oligoester and apolymerization catalyst, which is substantially free from any solvent,is provided continuously. The macrocyclic oligoester typically has thestructural repeat unit of formula (I) described above. The mixture ofthe macrocyclic oligoester and the polymerization catalyst iscrystallized partially and deposited onto a fabric material.

In still another aspect, the invention features a process forformulating a macrocyclic oligoester. In one embodiment, a solutionincluding a macrocyclic oligoester and a solvent is provided. Themacrocyclic oligoester typically has a structural repeat unit of formula(I) described above. The solvent often is continuously removed from thesolution at a temperature between about 180° C. and about 200° C. and ata pressure between about atmospheric pressure and about 10 torr. Thestep of solvent removal produces a substantially solvent-free moltenmacrocyclic oligoester. The substantially solvent-free moltenmacrocyclic oligoester then is sheared at a temperature below themelting point of the molten macrocyclic oligoester. In one embodiment,the shearing temperature is maintained between about 145° C. and about155° C., thereby forming a partially-crystallized macrocyclicoligoester. The partially-crystallized macrocyclic oligoester is shapedinto one or more shapes such as a pellet, a pastille, and/or a flake.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 is a schematic flow diagram of an embodiment of a solvent removalsystem.

FIG. 2 is a schematic flow diagram of an embodiment of a solvent removalsystem.

FIG. 3 is a schematic flow diagram of an embodiment of a solvent removalsystem.

FIG. 4 is a schematic flow diagram of an embodiment of a solvent removalsystem.

FIG. 5 is a schematic flow diagram of an embodiment of a process formaking pellets from a macrocyclic oligoester.

FIG. 6 is a schematic flow diagram of an embodiment of a pastillationprocess (e.g., making prepregs from a macrocyclic oligoester).

FIG. 7 is a schematic illustration of an embodiment of a process formaking a prepreg from a macrocyclic oligoester.

FIG. 8 is a schematic flow diagram of an embodiment of a solvent removalsystem.

FIG. 9 is a schematic flow diagram of an embodiment of a system forshaping macrocyclic oligoesters from a solution of macrocyclicoligoester and solvent.

FIG. 10 is a schematic flow diagram of an embodiment of a system forshaping macrocyclic oligoesters from a solution of macrocyclicoligoester and solvent.

DESCRIPTION

The processes of the invention are more efficient and economical thanexisting techniques because the isolation, formulation, and shapingprocesses may be carried out continuously and on a large scale. Thepurity of the macrocyclic oligoester may be effectively controlled bythe incorporation of multiple solvent removal apparatus where necessary.The isolation, formulation, and shaping processes also may bebeneficially linked, resulting in efficient mass production and loweredmanufacturing costs. Such linked processes avoid product and energywaste incurred when the isolation, formulation, and shaping processesare conducted separately. For example, macrocyclic oligoesters may beisolated in a molten state. The shaping process typically requires themacrocyclic oligoesters to be provided in a molten state. Accordingly,linking these processes reduces energy uses and increases productionefficiency.

For example of the benefits of continuous production, a macrocyclicoligoester having between about 80 ppm and about 400 ppm solvent may beproduced at a rate of between about 40 kg/hr and about 300 kg/hr using afeed solution having 20% by weight of macrocyclic oligoester, which canbe fed at a rate of between about 200 kg/hr and about 1,500 kg/hr. Forexample, after solvent removal, the macrocyclic oligoester, which issubstantially free from solvent, may be collected at a rate of betweenabout 80 kg/hr to about 250 kg/hr. Pellets and pastilles of formulatedand shaped macrocyclic oligoesters also can be produced at a similarrate.

Definitions

The following general definitions may be helpful in understanding thevarious terms and expressions used in this specification.

As used herein, a “macrocyclic” molecule means a cyclic molecule havingat least one ring within its molecular structure that contains 8 or moreatoms covalently connected to form the ring.

As used herein, an “oligomer” means a molecule that contains 2 or moreidentifiable structural repeat units of the same or different formula.

As used herein, an “oligoester” means a molecule that contains 2 or moreidentifiable ester functional repeat units of the same or differentformula

As used herein, a “macrocyclic oligoester” means a macrocyclic oligomercontaining 2 or more identifiable ester functional repeat units of thesame or different formula. A macrocyclic oligoester typically refers tomultiple molecules of one specific formula having varying ring sizes.However, a macrocyclic oligoester may also include multiple molecules ofdifferent formulae having varying numbers of the same or differentstructural repeat units. A macrocyclic oligoester may be a co-oligoesteror a higher order oligoester, i.e., an oligoester having two or moredifferent structural repeat units having an ester functionality withinone cyclic molecule.

As used herein, “an alkylene group” means —C_(n)H_(2n)—, where n≧2.

As used herein, “a cycloalkylene group” means a cyclic alkylene group,—C_(n)H_(2n-x-), where x represents the number of H's replaced bycyclization(s).

As used herein, “a mono- or polyoxyalkylene group” means[—(CH₂)_(m)—O—]_(n)—(CH₂)_(m)—, wherein m is an integer greater than 1and n is an integer greater than 0.

As used herein, “a divalent aromatic group” means an aromatic group withlinks to other parts of the macrocyclic molecule. For example, adivalent aromatic group may include a meta- or para-linked monocyclicaromatic group (e.g., benzene).

As used herein, “an alicyclic group” means a non-aromatic hydrocarbongroup containing a cyclic structure therein.

As used herein, “partially-crystallized macrocyclic oligomer” means amacrocyclic oligomer at least a portion of which is in crystalline form.Partially-crystallized macrocyclic oligomer may have various degrees ofcrystallinity ranging from 1% crystalline to 99% crystalline.Crystallinity imparts handleablility to the macrocyclic oligomer,enabling it to be shaped, for example.

As used herein, “a continuous process” means a process that operates onthe basis of a continuous flow of materials into and/or materials out ofthe process.

As used herein, “a polyester polymer composite” means a polyesterpolymer that is associated with another substrate such as a fibrous orparticulate material. Illustrative examples of particulate material arechopped fibers, glass microspheres, and crushed stone. Certain fillersand additives thus can be used to prepare polyester polymer composites.A fibrous material means more substrate, e.g., fiberglass, ceramicfibers, carbon fibers or organic polymers such as aramid fibers.

As used herein, “a fabric material” means any substrate useful inreceiving macrocyclic oligoesters during production and formulationprocesses and in preparing prepregs of macrocyclic oligomers. Typically,fabric materials include fiber tow, fiber web, fiber mat, and fiberfelt. The fabric materials may be woven or non-woven, unidirectional, orrandom.

Macrocyclic Oligoesters

Macrocyclic oligoesters that may be processed according to processes ofthis invention include, but are not limited to, macrocyclicpoly(alkylene dicarboxylate) oligomers typically having a structuralrepeat unit of the formula:

wherein R is an alkylene, a cycloalkylene, or a mono- or polyoxyalkylenegroup; and A is a divalent aromatic or alicyclic group.

Preferred macrocyclic oligoesters are macrocyclic oligoester of1,4-butylene terephthalate, 1,3-propylene terephthalate,1,4-cyclohexylenedimethylene terephthalate, ethylene terephthalate,propylene terephthalate, and 1,2-ethylene 2,6-naphthalenedicarboxylate,and macrocyclic co-oligoesters comprising two or more of the abovestructural repeat units.

Synthesis of the macrocyclic oligoesters may be achieved by contactingat least one diol of the formula HO—R—OH with at least one diacidchloride of the formula:

where R and A are as defined above. The reaction typically is conductedin the presence of at least one amine that has substantially no sterichindrance around the basic nitrogen atom. An illustrative example ofsuch amines is 1,4-diazabicyclo[2.2.2]octane (DABCO). The reactionusually is conducted under substantially anhydrous conditions in asubstantially water immiscible organic solvent such as methylenechloride. The temperature of the reaction typically is within the rangeof from about −25° C. to about 25° C. See, e.g., U.S. Pat. No. 5,039,783to Brunelle et al.

Macrocyclic oligoesters also can be prepared via the condensation of adiacid chloride with at least one bis(hydroxyalkyl)ester such asbis(4-hydroxybutyl) terephthalate in the presence of a highly unhinderedamine or a mixture thereof with at least one other tertiary amine suchas triethylamine. The condensation reaction is conducted in asubstantially inert organic solvent such as methylene chloride,chlorobenzene, or a mixture thereof See, e.g., U.S. Pat. No. 5,231,161to Brunelle et al.

Another method for preparing macrocyclic oligoesters or macrocyclicco-oligoesters is the depolymerization of linear polyester polymers inthe presence of an organotin or titanate compound. In this method,linear polyesters are converted to macrocyclic oligoesters by heating amixture of linear polyesters, an organic solvent, and atransesterification catalyst such as a tin or titanium compound. Thesolvents used, such as o-xylene and o-dichlorobenzene, usually aresubstantially free from oxygen and water. See, e.g., U.S. Pat. No.5,407,984 to Brunelle et al. and U.S. Pat. No. 5,668,186 to Brunelle etal.

It is also within the scope of the invention to process macrocyclic co-and higher order oligoesters using the methods of the invention.Therefore, unless otherwise stated, an embodiment of a composition,article, or process that refers to macrocyclic oligoesters also includesembodiments utilizing macrocyclic co-oligoesters and higher orderoligoesters.

Isolation of Macrocyclic Oligoesters

In one aspect, the invention generally features processes for isolatinga macrocyclic oligoester from a solution having a macrocyclic oligoesterand a solvent in a manner that does not require use of an anti-solvent.In one embodiment, the process includes removing solvent to yield amacrocyclic oligoester substantially free from solvent. A solutionincluding a macrocyclic oligoester and a solvent is provided. Thesolvent is then removed without the use of anti-solvent. In oneembodiment, the solvent is removed under reduced temperature conditions.In another embodiment, the solvent is removed under elevated pressureconditions. In another embodiment, the solvent is removed under acombination of both elevated temperature and reduced pressureconditions. The macrocyclic oligoester substantially free from thesolvent then typically is collected. In one embodiment, the solvent iscontinuously removed from the solution including a macrocyclicoligoester and a solvent. In another embodiment, the macrocyclicoligoester substantially free from the solvent is continuouslycollected.

There is no limitation to the concentration of macrocyclic oligoester inthe solution. In one embodiment, the solution of a macrocyclicoligoester and a solvent (the input or feed solution) contains betweenabout 1% and about 50% by weight macrocyclic oligoester. In otherembodiments, the feed solution contains between about 3% and about 50%,between about 5% and about 40%, between about 5% and about 20%, betweenabout 3% and about 10%, or between about 1% to about 3% by weightmacrocyclic oligoester. The solution may contain one or two or moredifferent solvents. “Solvent” used herein refers to the solvent orsolvents contained in the feed solution.

Solvent removal may be carried out at an elevated temperature, at areduced pressure, or both. In one embodiment, the feed solution isheated at an elevated temperature and a reduced pressure to remove thesolvent from the solution. The resulting macrocyclic oligoester issubstantially free from solvent. A macrocyclic oligoester issubstantially free from solvent if the solvent content is less than 200ppm. Preferably, the solvent content is less than 100 ppm. Morepreferably the solvent content is less than 50 ppm or less than 10 ppm.

The processing temperature and pressure for solvent removal are selectedaccording to factors including the solvent to be removed, the solventremoval device(s) used, the desired time of purification, and themacrocyclic oligoester being isolated. In one embodiment, the step ofremoving solvent is conducted at a temperature within a range fromambient temperature to about 300° C. In other embodiments, the step ofremoving solvent is conducted from about 200° C. to about 260° C., fromabout 230° C. to about 240° C., or from about 180° C. to about 200° C.

The pressure at which solvent removal is conducted can vary fromatmospheric pressure to about 0.001 torr. In one embodiment, thepressure is within a range from 0.001 torr to about 0.01 torr. In otherembodiments, the pressure is within a range from atmospheric pressure toabout 10 torr, from about 10 torr to about 5.0 torr, from about 5.0 torrto about 1.0 torr, from about 1.0 torr to about 0.1 torr, or from about0.1 torr to about 0.01 torr.

Solvent removal may be accomplished in almost any apparatus, e.g.,vessels or devices or a combination of apparatus. Non-limiting examplesof solvent removal apparatus that may be employed include a rising filmevaporator, a falling film stripper, a thin film evaporator, a wipedfilm evaporator, a molecular still, a short path evaporator, acentrifuge, and a filter. The terms evaporator and stripper may be usedinterchangeably. In one embodiment, the rising film evaporator may be atubular heat exchanger. A rising film evaporator is an apparatus used tovaporize part or all of the solvent from a solution where the solutionis introduced to the bottom of the evaporator. A falling film stripperis an evaporative device for the removal of vapors from solution, wherethe solution is introduced to the top of the apparatus and travels tothe bottom of the apparatus. A thin film evaporator is an apparatus thatgenerates and exposes a thin film of material for evaporation and hasthe vapor condenser outside of the evaporator. A wiped film evaporatoris an apparatus that generates and exposes a thin film of material towiping or agitation to provide evaporation. A short path evaporatorgenerates and exposes a thin film of material for evaporation and hasthe vapor condenser inside the evaporator. In some embodiments, theshort path evaporator exposes the thin film to wiping or agitation toprovide evaporation. A molecular still is an apparatus that utilizes acondenser inside the body of the still. One or more solvent removaldevice may be employed in accordance with the invention. In oneembodiment, each solvent removal apparatus used in the process removesbetween about 80% and about 90% of the solvent. In one embodiment,multiple solvent removal apparatus are employed to achieve the desireddryness in the macrocyclic oligoester substantially free from solvent.

FIG. 1 schematically illustrates one embodiment of a solvent removalsystem 2. An input solution 10 is pumped into a rising film evaporator11. As the input solution travels up the first rising film evaporator11, some of the solvent vaporizes and is separated from the solution.This solution and the vapor then travels through a flash device 15. Aflash device is an apparatus that is used to separate the liquid and thegas phase. The liquid phase solution then is pumped into a second risingfilm evaporator 21. After traveling through another flash device 25, thevapor phase solvent that is removed from flash devices 15 and 25 ispumped through paths 20′ and 20″, respectively, and is condensed incondensers 52 and 54. The condensers 52 and 54 change any vapor phasesolvent in paths 20′ and 20″ into a liquid phase. Optionally, effluentcontaining removed solvent may be discharged from condensers 52 and 54.The condensed solvent is then collected in the liquid receiver 27. Thesolution containing macrocyclic oligoester is pumped from flash device25 into a falling film stripper 31. In one embodiment, the vaporsremoved in the falling film stripper 31 also travel through the flashdevice 25. An output product 130, which is substantially free fromsolvent, is pumped out of the falling film stripper 31. In oneembodiment, the output product 130 is molten.

Substantially all of the solvent in the input solution can be removedfrom the macrocyclic oligoester to form a macrocyclic oligoestersubstantially free from solvent In one embodiment, the macrocyclicoligoester substantially free from solvent may contain about 200 ppm orless of solvent. In other embodiments, the macrocyclic oligoestersubstantially free from solvent may contain about 100 ppm or less ofsolvent, about 50 ppm or less of solvent, and about 10 ppm or less ofsolvent The amount of solvent remaining in the macrocyclic oligoestersubstantially free from solvent may be measured using chromatographictechniques such as gas chromatography, GCMS, or HPLC.

In determining an appropriate solvent stripping system to employ in aparticular process, factors that need to be considered include theconcentration of macrocyclic oligoester in the feed solution, thedesired dryness and/or purity of the product, the solvent to be removed,and the desired length of time for solvent removal. For example,starting with a relatively dilute feed solution (i.e., low percentage ofmacrocyclic oligoester), more solvent removal steps and/or time may benecessary to produce a substantially solvent free macrocyclicoligoester. Conversely, a concentrated feed solution of macrocyclicoligoester may require fewer solvent removal steps and/or time.

Generally and in one embodiment, solvent is removed from an inputsolution by exposing the input solution to an elevated temperature and areduced pressure in a first rising film evaporator. The input solutionthen travels to a second rising film evaporator where it is exposed toan elevated temperature and a reduced pressure. Finally, the inputsolution travels to a falling film stripper and a macrocyclic oligoestersubstantially free from solvent is collected from the falling filmstripper.

In another general embodiment, solvent is removed from an input solutionby exposing the feed solution to an elevated temperature and a reducedpressure in a first rising film evaporator. The input solution thentravels through a first flash device. The solvent that is removed in thefirst rising film evaporator and the first flash device travels to afirst condenser and the remainder of the input solution travels to asecond rising film evaporator where it is exposed to an elevatedtemperature and a reduced pressure. The input solution then travelsthrough a second flash device. The solvent that is removed in the secondrising film evaporator and the second flash device travels to a secondcondenser. The solvent that has traveled through the first condenser andthe second condenser is transported to a liquid receiver. The remainderof the input solution and the solvent travels to a falling filmstripper. Optionally, the sparger may operate at the same time as thefalling film stripper. Alternatively, a sparger removes gasses andvapors from the input solution after it has traveled through thestripper. Thereafter, a macrocyclic oligoester substantially free fromsolvent is collected.

When preparing macrocyclic oligoesters by depolymerizing linearpolyesters, dilute conditions may be desired to promote cyclization andto increase the yield of macrocylcic oligoesters. As a result, themacrocyclic oligoester solution (e.g., the product solution of adepolymerization reaction) may be dilute (e.g., a 1% by weightmacrocyclic oligoester solution).

FIG. 2 schematically illustrates an embodiment of a system 1 for solventremoval that is typically employed where the solution is dilute (e.g.,less than about 3% by weight macrocyclic oligoester). A linear polyesterdepolymerization reaction product solution (i.e., the input solution)110 is pumped into a rising film evaporator 111. Some of the solvent inthe solution transitions into the vapor phase as it travels up therising film evaporator 111 and it then travels though a flash device115. The solution then is pumped into a second rising film evaporator121. Thereafter the solution travels through another flash device 125.The solution that exits the flash device 125 travels along path 135 andhas a higher macrocyclic oligoester concentration (e.g., an increasefrom about 1% to about 3%). The vapor phase solvent that is removed fromflash devices 115 and 125 travels along paths 120′ and 120″, iscondensed in condensers 152 and 154, and is collected in a liquidreceiver 127. The macrocyclic oligoester solution that exits the flashdevice 125 then travels along path 135 to a filter 141, which removesany remaining linear polyester and/or catalyst from the depolymerizationreaction product solution. The filter 141 may be, for example, a Niagarafilter or a Sparkler filter. A Niagara filter is a multiple tray filteravailable from Baker Hughes Corporation (Houston, Tex.). Similarly, aSparkler filter is a multiple tray filter apparatus available fromSparkler Filters, Inc. (Conroe, Tex.). In one embodiment, a centrifugeis employed alternatively or in addition to the filter 141. A resultingoutput solution 190 exiting filter 141 may become the input solution inthe next solvent removal step.

The output solution 190 may have a macrocyclic oliogester concentrationof about 3%. In one embodiment, the rising film evaporator 111 is heldat a temperature between about 180° C.–185° C. at atmospheric pressure.In another embodiment, the rising film evaporator 121 is held attemperature between about 180° C.–185° C. at atmospheric pressure. Inother embodiments, each rising film evaporator 111 and 121 is held at atemperature between about 120° C. to 280° C. at a pressure ranging fromabout 0.001 torr to about atmospheric pressure.

Referring again to FIG. 1, when the concentration of macrocyclicoligomer input solution 10 is about 3%, two additional rising filmevaporators (not shown) may be placed in series between the first risingfilm evaporator 11 and the second rising film evaporator 21. The twoadditional rising film evaporators may employ similar conditions as thefirst rising film evaporator 11 and use steam to heat the macrocyclicoligomer and the solvent (e.g., at about 150° C. under a pressure ofabout 100 torr).

In one embodiment, the rising film evaporator employs steam to heat thesolution to a temperature between about 120° C. to 200° C. In yetanother embodiment, the rising film evaporator employs hot oil to heatthe solution to between about 200° C. to about 280° C. The rising filmevaporators may be operated at pressures ranging from about 0.001 torrto about atmospheric pressure. In one embodiment, between about 80% andabout 90% of the solvent in the input solution is removed by each risingfilm evaporator. Where the input solution has a relatively lowconcentration of macrocyclic oligoester, multiple rising filmevaporators may be employed in multiple steps. In one embodiment,multiple solvent removal apparatus are employed to achieve the desireddryness in the macrocyclic oligoester substantially free from solvent.

FIG. 3 schematically illustrates another embodiment of a solvent removalsystem 3. The system shown in FIG. 3 may be used alone or in combinationwith that of FIG. 2. An input solution 210 is pumped into a first risingfilm evaporator 211. Thereafter, the solution travels through a firstflash device 255. Condenser 252 captures the vaporized solvent that isremoved in the first rising film evaporator 211 and the first flashdevice 255. The solution then travels through a second rising filmevaporator 221 to a second flash device 265. Condenser 254 captures thevaporized solvent that is removed in the second rising film evaporator221 and the second flash device 265. The solution then travels through athird rising film evaporator 231. Subsequently, the solution travelsthrough a third flash device 275. Condenser 256 captures the vaporizedsolvent that is removed in the third rising film evaporator 231 and thethird flash device 275. After traveling through the third flash device275, the solution travels through the falling film stripper 241. Amacrocyclic oligoester output product 230 substantially free fromsolvent is pumped out of the falling film stripper 241. In oneembodiment, the macrocyclic oligoester 230 is in a molten state. Thevaporized solvent that is removed from flash device 255, 265, and 275travels along paths 220′, 220″, and 220′″ and is condensed in condensers252, 254 and 256, and is collected in the liquid receiver 227.

In another embodiment, the first rising film evaporator has about 20square feet of evaporation surface area and is maintained at aboutatmospheric pressure and a temperature of about 185° C. The secondrising film evaporator has about 5 square feet of evaporation surfacearea and is maintained at a pressure of about 1 torr and at atemperature ranging between about 185° C. and about 190° C. The thirdrising film evaporator has about 1 square foot of evaporation surfacearea and is maintained at a pressure of about 1 torr and at atemperature ranging between about 185° C. and about 190° C. In thisembodiment, the first rising film evaporator, having a relatively largeevaporation surface area and being run at atmospheric pressure,typically removes the bulk of solvent from the input solution.

Generally and in one embodiment of the invention, solvent is removedfrom an input solution of a macrocyclic oligoester by exposing the inputsolution to an elevated temperature and a reduced pressure in a firstshort path evaporator. A short path evaporator is used to vaporize partor all of the solvent from a solution. A short path evaporator canoperate at a low pressure because the condenser is located inside of theevaporator. The input solution may then travel to a second short pathevaporator where it is exposed to an elevated temperature and a reducedpressure.

FIG. 4 schematically illustrates another embodiment of a solvent removalsystem 4. An input solution 310 of a 3% by weight macrocyclic oligoestersolution is pumped into the top of a falling film stripper 341.Thereafter, the solution travels through a flash device 315. The solventthat is vaporized in the falling film stripper 341 and the first flashdevice 315 travels through a path 320′ to a condenser 352, and isremoved from the solution. The solvent that has traveled through thecondenser 352 is transported to a liquid receiver 327. The solutiontravels to the short path evaporator 311. In the short path evaporator311 the solution is exposed to an elevated temperature and reducedpressure. The solvent that is vaporized in the short path evaporator 311is condensed within the short path evaporator 311 and removed from thesolution. The solvent removed within the short path evaporator 311 istransported through a path 320″ to a liquid receiver 327. A macrocyclicoligoester output product 330 substantially free from solvent exits theshort path evaporator 311. In one embodiment, the macrocyclic oligoester330 is in a molten state. A macrocyclic oligoester substantially freefrom solvent is collected from the short path evaporator 311.

In one exemplary embodiment the input solution 310 of macrocyclicoligoester is heated to a temperature of about 180° C. and is pumpedinto the top of the falling film stripper 341 at a rate of about 5900kg/hr. The falling film stripper 341 is maintained at a temperature ofabout 180° C. and at about atmospheric pressure. The solution exits thebottom of the falling film stripper 341 at a temperature of about 180°C. The solution enters the flash device 315, which is held atatmospheric pressure and at a temperature of about 180° C. The solutionexiting the flash device 315 that enters the short path evaporator 311is at a temperature of about 180° C. The short path evaporator 311 has2.4 m² of surface area, is held at a temperature of about 210° C. and ata pressure of about 5 torr. The macrocyclic oligoester output product330 exits the short path evaporator 311 at a rate of about 181 kg/hr andat a temperature of about 210° C. The output product 330 contains lessthan 100 ppm of solvent. A suitable falling film stripper 341, flashdevice 315, and short path evaporator 311 that may be employed inaccordance with this exemplary embodiment are available from InconProcessing Technology (Batavia, Ill.).

In one embodiment, a compressor may be employed in place of a condenser.In another embodiment, the compressed gas or the condensed gas exitingthe compressor or the condenser, respectively, may be employed as theheat input to one or more of the stripping apparatus and/or theevaporating apparatus. For example, where a shell and tube heatexchanger is employed, the compressed gas exiting a compressor may befed to the shell side of the heat exchanger.

Generally, where short path evaporators have been employed in thesolvent removal process, a sparger may not be necessary to obtain amacrocyclic oligoester substantially free from solvent. Short pathevaporators can operate effectively under lower vacuum and at lowertemperature conditions, thereby potentially saving energy costs. Also,the time required by the sparging step and the cost of maintainingsparging equipment are avoided when short path evaporators are employed.

Systems, apparatus, and equipment that may be employed or adapted toperform the processes described herein are commercially available, forexample, from Artisan Industries Inc. of Waltham, Mass. and from LCI ofCharlotte, N.C. Suitable rising film evaporators include heat exchangersavailable from Troy Boiler (Albany, N.Y.). Suitable falling filmstrippers, condensers and flash devices may be supplied by ArtisanIndustries Inc. (Waltham, Mass.) and Incon Processing Technology(Batavia, Ill.). Suitable short path evaporators are available fromIncon Processing Technology Batavia, Ill.). Suitable liquid receiversare available from suppliers including, Artisan Industries Inc.(Waltham, Mass.) and Incon Processing Technology (Batavia, Ill.)

Shaping Macrocyclic Oligoesters

In another aspect, the invention features a process for shaping apartially-crystallized macrocyclic oligoester. This process includesproviding a substantially solvent-free molten macrocyclic oligoester.The substantially solvent-free molten macrocyclic oligoester is shearedto form a partially-crystallized macrocyclic oligoester, which can beshaped.

In one embodiment, the substantially solvent-free molten macrocyclicoligoester is continuously sheared to form a partially-crystallizedmacrocyclic oligoester. In another embodiment, shaping of thepartially-crystallized macrocyclic oligoester is continuous. In yetanother embodiment, the molten macrocyclic oligoester is continuouslysheared and the partially-crystallized macrocyclic oligoester iscontinuously shaped.

Once substantially free from solvent the macrocyclic oligoester, whichmay be a molten liquid at the solvent-removal temperature, is cooled andsolidified into a usable form. When molten macrocyclic oligoester (suchas macrocyclic (1,4-butylene terephthalate)) is cooled quickly, it istypically amorphous. In its amorphous state, the macrocyclic oligoesteris sticky and “droplets” tend to agglomerate into a large mass.Amorphous macrocyclic oligoester also absorbs water from the atmosphere,which can be detrimental to subsequent processing.

Shear-induced partial-crystallization is used to facilitatecrystallization of the macrocyclic oligoester. According to embodimentsof the invention, an extruder, a scraped surface crystallizer, and/or ashear mixer are employed to partially-crystallize the product to form apartially-crystallized macrocyclic oligoester. A shear mixer includesany crystallizer that facilities crystallization by shear mixing. Theextruder may be employed to extrude the macrocyclic oligoester at atemperature below the melting point of the macrocyclic oligoester,thereby forming a partially-crystallized macrocyclic oligoester.Shearing may include shearing, cooling, or shearing and coolingsimultaneously.

Suitable product forms (e.g., pellets, pastilles, flakes, and prepregs)that are stable in the environment and easy to handle may be obtained bythese methods. The partially-crystallized macrocyclic oligoester thenmay be collected. The collection may be continuously performed dependingon the application.

Two or more processes of the invention may be carried outsimultaneously. In one embodiment, an extruder removes solvent from thesolution of macrocyclic oligoester to form a substantially solvent-freemolten macrocyclic oligoester that the extruder shears to form apartially-crystallized macrocyclic oligoester that is shaped into apellet

The macrocyclic oligoester may be sheared at a temperature that is lowerthan the melting point of the macrocyclic oligoester. In one embodiment,the shearing step is conducted at a temperature between about 100° C.and about 165° C. In another embodiment, the shearing step is conductedat a temperature between about 145° C. and about 155° C.

Additionally, one or more of various additives and fillers can beincorporated into the macrocyclic oligoester, before, during or aftersolvent removal to yield a fully formulated product. For example, in themanufacture of an article, various types of fillers may be included.Filler often is included to achieve a desired property, and may bepresent in the resulting polyester polymer. The filler may be present toprovide stability, such as chemical, thermal or light stability, to theblend material or the polyester polymer product, and/or to increase thestrength of the polyester polymer product. A filler also may provide orreduce color, provide weight or bulk to achieve a particular density,provide flame resistance (i.e., be a flame retardant), be a substitutefor a more expensive material, facilitate processing, and/or provideother desirable properties as recognized by a skilled artisan.

Illustrative examples of fillers are, among others, fumed silicate,titanium dioxide, calcium carbonate, chopped fibers, fly ash, glassmicrospheres, micro-balloons, crushed stone, nanoclay, linear polymers,and monomers. One or more fillers may be added before, during, or afterthe polymerization reaction between a macrocyclic oligoester and acyclic ester. For example, fillers may be added to a substantiallysolvent-free macrocyclic oligoester. Optionally the filler may be addedwhen the substantially solvent-free macrocyclic oligoester is in moltenform. Also, fillers can be used to prepare polyester polymer composites.

In some embodiments, additional components (e.g., additives) are addedto the macrocyclic oligoesters. Illustrative additives includecolorants, pigments, magnetic materials, anti-oxidants, UV stabilizers,plasticizers, fire-retardants, lubricants, and mold releases. In otherembodiments, one or more catalysts are added to the macrocyclicoligoester. Exemplary catalysts that may employed in accordance with theinvention are described below.

Formulating Macrocyclic Oligoesters

In another aspect, the invention features processes for formulatingmacrocyclic oligoesters and processes for making prepregs frommacrocyclic oligoesters and polymerization catalysts.

In one embodiment, a mixture of a molten macrocyclic oligoester and apolymerization catalyst substantially free from solvent is provided. Themixture of the molten macrocyclic oligoester and polymerization catalystis deposited onto a fabric material to form a prepreg. In oneembodiment, the molten macrocyclic oligoester and polymerizationcatalyst are partially-crystallized prior to being deposited onto thefabric material.

A mixture of a molten macrocyclic oligoester and a polymerizationcatalyst substantially free from solvent may be continuously provided.The mixture of the macrocyclic oligoester and the polymerizationcatalyst may be partially crystallized. In one embodiment, the mixtureis continuously partially crystallized. The partially-crystallizedmixture of the macrocyclic oligoester and the polymerization catalystthen may be deposited onto a fabric material. In another embodiment, thepartially-crystallized mixture is continuously deposited onto a fabricmaterial.

In other embodiments, a macrocyclic oligoester (e.g., pellets) is fed toa hot mixing device (e.g., an extruder or a Readco mixer) with othersolid or liquid additives (e.g., stabilizers or polymerizationcatalysts) with or without fillers. The mixing device partially meltsthe macrocyclic oligoester into a paste to enhance mixing and flow. Theformulated product, which remains partially crystalline, then is formedinto shapes such as pellets, flakes, pastilles, and/or applied directlyto a fabric material to male a prepreg. This method typically avoids theproblems of handling amorphous macrocyclic oligoester.

In yet other embodiments, the partially-crystallized mixture of moltenmacrocyclic oligoester and polymerization catalyst is deposited onto afabric material. In certain embodiments the molten macrocyclicoligoester and polymerization catalyst are shear mixed in a shear mixer;alternatively, they may be processed in an extruder. The shear-mixingmay be conducted at a temperature between about 145° C. and about 155°C. The fabric material(s) may be selected from the group of fiber tow,fiber web, fiber mat, felt, non-woven material, and random and wovenmaterial.

Prior to partial-crystallization, the molten macrocyclic oligoester maycontain less than about 200 ppm of solvent Preferably, the moltenmacrocyclic oligoester contains less than about 100 ppm of solvent. Morepreferably, the molten macrocyclic oligoester contains less than about50 ppm of solvent or less than about 10 ppm of solvent

The partially-crystallized mixture of the macrocyclic oligoester and thepolymerization catalyst may be deposited onto the fabric material in apre-selected array. In addition, the fabric material having the mixtureof macrocyclic oligoester and polymerization catalyst deposited thereonmay be formed into a desired shape, for example, an autobody panelshape. One or more additives may be added to the molten macrocyclicoligoester. Exemplary additives may be selected from the group ofcolorants, pigments, magnetic materials, anti-oxidants, UV stabilizers,plasticizers, fire-retardants, lubricants, and mold releases.

In one embodiment, the molten macrocyclic oligoester and polymerizationcatalyst are partially-crystallized prior to being deposited onto thefabric material. The mixture of molton macrocyclic oligoester andpolymerization catalyst may be partially-crystallized by, for example,shear mixing. In certain embodiments, shear mixing is conducted within atemperature range between about 145° C. and about 155° C. In otherembodiments the mixture of molton macrocyclic oligoester andpolymerization catalyst is partially-crystallized by extrusion, which isoften conducted within a temperature range between about 145° C. andabout 155° C.

The partially-crystallized mixture of macrocyclic oligoester andpolymerization catalyst may be deposited onto the fabric material indiscrete droplets of a selected size according to a pattern of apre-selected array. In certain embodiments, the molten macrocyclicoligoester is mixed with one or more additive(s) and/or filler(s). Thefabric material may be selected from the group of fiber tow, fiber web,fiber mat, felt, non-woven material, random, and woven material. Thefabric material employed in a prepreg may vary depending on the end useapplication of the prepreg. Also, the fiber used to make the fibermaterial, or any fiber sizing agents or other agents present on thefiber material, may impact the suitability of the fiber material for usein a prepreg. For example, some catalysts and/or macrocyclic oligoesterand polymerization catalyst mixtures may interact with the fibers and/orany sizing or other agents that are present on the fabric material.

In some embodiments, the partial crystallization step occurscontinuously. In other embodiments, the partially-crystallized mixtureof macrocyclic oligoester and the polymerization catalyst iscontinuously deposited on the fabric material. In still otherembodiments, the process of malting the prepreg is continuous wherebythe mixture of a molten macrocyclic oligoester and a polymerizationcatalyst, which is substantially free from solvent, is continuouslyprovided, continuously partially-crystallized, then continuouslydeposited onto a fabric material.

In another embodiments, the process of solvent removal and the processof prepreg formation are combined, creating a continuous process fromthe feed solution of a macrocyclic oligoester to formation of prepregsof macrocyclic oligoester substantially free from the solvent. Theprepregs may contain one or more additives and a polymerizationcatalyst. Such continuous processes may provide advantages in manyaspects such as in reducing energy cost and processing time andoptimizing equipment usage.

FIG. 5 schematically illustrates one embodiment of a process 5 formaking pellets from a molten product with an underwater pelletizer. Inthis embodiment, a molten macrocyclic oligoester 530, which issubstantially free from solvent, is fed into a shear mixer 360. Theshear mixer 360 is connected to a temperature control loop (not shown).The shear mixer 360 may be a Readco mixer (York, Pa.), which is like atwin screw extruder, but less heavy duty. The molten macrocyclicoligoester within the shear mixer 360 is typically cooled to atemperature between about 80° C. and about 140° C., preferably betweenabout 130° C. and about 140° C. By lowering the temperature in the shearmixer 360, the macrocyclic oligomer is crystallized partially and ispaste-like. Generally, the partially-crystallized macrocyclic oligomeremployed to make pellets 435 measures between about 3000 cp.(centipoise) and about 5000 cp., which typically indicates that about30% of the macrocyclic oligomer is crystallized.

The partially-crystallized macrocyclic oligomer travels from the shearmixer 360 to a diverter valve 365. The diverter valve 365 may be used todivert the product from the process to, for example, a bucket when thepelletizer starts up. The diverter 365 typically is used to ensure thatthe partially-crystallized macrocyclic oligoester is traveling to theupstream cutter 370 at a minimum velocity. A suitable diverter 365 and asuitable cutter 370 may be available from Gala Industries Eagle Rock,Va.), Incon Processing Technology (Batavia, Ill.), and/or ArtisanIndustries Inc. (Waltham, Mass.). After a minimum velocity is achieved,the partially-crystallized macrocyclic oligomer travels to the cutter370. At the cutter 370, the partially-crystallized paste-likemacrocyclic oligomer is cut into the shape of pellets in a slurry ofwater. One or more pellets may be cut by the cutter 370 at once. Thepellets are then removed from the slurry of water into a separator 380.The separator 380 may be a screen, which may be a moving belt. Asuitable separator 380 may be available from Gala Industries (EagleRock, Va.), Incon Processing Technology (Batavia, Ill.), and/or ArtisanIndustries Inc. (Waltham, Mass.). Subsequently, the pellets 435 aredried in a dryer 385 and then transferred to a pellet hopper 395 and apackager 550. The dryer 385 may be a fluid bed dryer available fromKason Corporation (Milburn, N.J.). A suitable pellet hopper 395 and asuitable packager 550 may be available from Gala Industries (Eagle Rock,Va.), Incon Processing Technology (Batavia, Ill.), and/or ArtisanIndustries Inc. (Waltham, Mass.). As depicted, the water that wasseparated from the pellets is recycled through a sump 384 and a watercirculation pump 388. A suitable sump 384 and a suitable circulationpump 388 may be available from Gala Industries (Eagle Rock, Va.), InconProcessing Technology (Batavia, Ill.), and/or Artisan Industries Inc.(Waltham, Mass.).

FIG. 6 schematically illustrates an embodiment of a process 6 for makingeither prepreg or pastille from a molten product utilizing apastillation process. A molten macrocyclic oligoester 630, which issubstantially free from solvent, is fed into a shear mixer 360 that isconnected to a temperature control loop (not shown) to control thetemperature of the shear mixer 360. The molten macrocyclic oligomerwithin the shear mixer 360 is typically cooled to a temperature betweenabout 80° C. and about 140° C., preferably between about 130° C. andabout 140° C.

In certain embodiments, the temperature control loop maintains the shearmixer 360 at a temperature of about 100° C. In other embodiments, theshear mixer 360 is an extruder. In yet other embodiments, the shearmixer 360 is a Readco mixer (York, Pa.), which is like a twin screwextruder, but less heavy duty.

By lowering the temperature in the shear mixer, the macrocyclic oligomeris partially crystallized and becomes paste-like. The temperature and/orthe level of shear provided to produce the paste-like macrocyclicoligomer varies according to the composition of the macrocyclicoligomer, including the presence of any additives. Generally, thepartially-crystallized macrocyclic oligomer employed to make pastillesmeasures between about 500 cp. and about 1000 cp., which typicallyindicates that it is between about 15% and about 20% crystallized. Themolten macrocyclic oligomer may contain some residual solvent (e.g.,between about 100 ppm and about 10 ppm) as the molten resin enters theshaping process at a temperature between about 150° C. and about 200° C.

Both prepregs and pastilles can be made from the partially-crystallizedand paste-like macrocyclic oligomer utilizing pastillation equipment.The partially-crystallized paste-like macrocyclic oligomer travels fromthe shear mixer 360 and enters a droplet generator 390. The dropletgenerator 390 is employed to make desired sized droplets of macrocyclicoligoester. In one embodiment, a Sandvik Rotoformer available fromSandvik Process Systems of Totowa, N.J. is employed to make droplets.When pastilles 425 are manufactured, the droplet generator 390 may droppastilles 325 directly onto a moving belt 500.

The moving belt 500 may be of any length and size and is typicallybetween about 50 feet to about 100 feet in length The bottom side of themoving belt 500 may be cooled, for example, by providing waterunderneath the moving belt 500. The length of the moving belt 500 andthe cooling method can be selected to cool the pastilles 425 before theend of the moving belt 500. In some embodiments, a scraping bar (notshown) is employed at the end of the moving belt 500 to remove thepastilles 425 from the moving belt 500. In one embodiment, a moving belt500 available from Sandvik Process Systems of Totowa, N.J. is employed.

When a prepreg 445 is manufactured, the droplet generator 390 may dropthe material 415 (e.g., macrocyclic oligoester plus a polymerizationcatalyst) onto a fabric material 600 that is fed onto the moving belt500. The length of the moving belt 500 and any cooling method will beselected to cool the material 415 into the fabric material 600, formingthe prepreg 445.

In some embodiments, an underwater pelletizer is used for makingpellets. In For example, a Gala type underwater pelletizer (availablefrom Gala Industries, Inc. of Eagle Rock, Va.) may be used for makingpellets. Alternatively, a pastillator may be used for forming pastilles.For example, a Sandvik Rotoformer (available from Sandvik ProcessSystems of Totowa, N.J.) may be used to form pastilles.

In yet another aspect of the invention, the process of solvent removaland the process of shaping a partially-crystallized macrocyclicoligoester are combined, creating a continuous process from feeding asolution of a macrocyclic oligoester to shaping the macrocyclicoligoester. For example, in one embodiment, the process of solventremoval and the process of pastillation may be combined, therebycreating a continuous process from input solution of a macrocyclicoligoester to pastilles of macrocyclic oligoester substantially freefrom the solvent. In one embodiment, a solution of macrocyclicoligoester is provided. During the solvent removal process, thetemperature often is elevated to between about 180° C. and about 200°C., and the pressure maintained between about atmospheric pressure andabout 10 torr. In these embodiments, the solvent is continuously removedto produce a substantially solvent-free molten macrocyclic oligoester.

The substantially solvent-free molten macrocyclic oligoester may besheared at a temperature below the melting point of the moltenmacrocyclic oligoester to form a partially-crystallized macrocyclicoligoester. The shearing temperature may be maintained at, for example,between about 145° C. and about 155° C. Subsequently, thepartially-crystallized macrocyclic oligoester may be formed into anydesirable shapes including pellets, pastilles, and flakes.

Additives and fillers may be formulated with a macrocyclic oligoester orwith a mixture of a macrocyclic oligoester and a catalyst. In oneembodiment, the additive(s) and/or filler(s) are formulated with amacrocyclic oligoester while the latter macrocyclic oligoester iscompletely molten. In other embodiments, the additive(s) and/orfiller(s) are formulated with a macrocyclic oligoester while the lattermacrocyclic oligoester is partially molten and partially crystalline. Inyet other embodiments, the additive(s) and/or filler(s) are formulatedwith a macrocyclic oligoester while the macrocyclic oligoester iscompletely crystalline. The formulated macrocyclic oligoester isprepared into a prepreg in the form of pastilles on a fabric material.

Pastille prepregs may be prepared from a blend material that includesmacrocyclic oligoesters. In one embodiment, the invention relates tomethods for preparing pastille thermoplastic prepregs based on a blendmaterial that includes at least one macrocyclic oligoester and at leastone polymerization catalyst.

Thermoplastic prepregs typically have been produced with the resin closeto the fiber. If the melt viscosity of the resin is high, the resinneeds to be close to the fiber in order to wet-out the fiber properly.This typically is the case with thermoplastic prepregs made using a hotmelt method with thermoplastic powder, co-mingled tows of reinforcingfiber and thermoplastic fiber, or co-woven fabrics. These materialsrequire a process which often includes three steps: 1) heating andmelting the resin, 2) wetting out of the fiber and consolidating, and 3)cooling down and solidifying.

Macrocyclic oligoesters, as discussed above, melt to a low viscositythat may be many orders of magnitude lower than the viscosity ofconventional thermoplastics. Thus, combining and wetting-out ofmacrocyclic oligoesters (when melted) with fillers and/or reinforcingfibers during the heating cycle of a process can be done much moreeasily than conventional thermoplastics. Hence, in prepreg fabrics madewith macrocyclic oligoesters, the resin does not need to be distributedas close to the fiber (i.e., each and every fiber) as is needed forconventional thermoplastics. That is, resin can be placed at discretelocations, but melt and flow to wet-out the entire fabric when the resinis melted.

When a prepreg is made with a blend material that includes a macrocyclicoligoester, the blend material can be a one-part ready-to-use systemwith a catalyst already included. FIG. 7 illustrates one embodiment ofthe invention, a process 7 for making a prepreg 445 from a macrocyclicoligoester or a blend material of macrocyclic oligoester with one ormore other components such as a polymerization catalyst. The processallows the making of a prepreg 445 that has the desired resin and fabricmaterial in a pre-selected ratio. Such prepregs can simplify upstreamprocesses employing prepregs.

Referring to FIG. 7, a blend material (e.g., a one-part system) ismelted and applied to a reinforcing fabric 600 in discreet resin drops415 and then cooled before significant polymerization takes place. Themolten resin 505 is pumped into a channel in the bottom of a rotatingcylinder 510 and comes out through the holes 507 in the cylinder eachtime the holes 507 line up with the channel. In one embodiment, arotating cylinder 510 available from Sandvik Process Systems of Totowa,N.J. is employed in the process. Consequently, liquid drops of resinfall at predetermined intervals onto a moving belt 500 (e.g., a steelbelt). These discrete resin drops 415 can be arranged in a pre-selectedarray (e.g., a pattern) so that the amount of resin is uniform per unitfabric area (if uniformity is desired) and is of a desired value. In oneembodiment, the amount of resin per unit fabric area ranges from about3% by weight resin to about 97% by weight resin. In another embodiment,the amount of resin per unit fabric area ranges from about 30% by weightresin to about 80% by weight resin.

The amount, pattern, and spacing of the dropped resin determine the“average” ratio of fabric material to resin before the resin is meltedand distributed throughout the fabric material. There is no limitationas to the amount and pattern of the resin drops as long as the desiredpreregs are formed. The ratio of fabric material to resin may be uniformor varied across the prepreg and can be manipulated by controlling thesize of each drop of resin and the space between them.

FIG. 8 illustrates a schematic flow diagram of an embodiment of asolvent removal system where the solvent removal system 1 illustrated inFIG. 2 is linked with the solvent removal system 2 illustrated inFIG. 1. According to this embodiment, which is typically employed wherethe linear polyester depolymerization reaction product solution (i.e.,the input solution) is a dilute (e.g., about 1% by weight macrocyclicoligoester), input solution 110 is first processed though system 1 toyield a resulting output solution 190. The solution 190 that is theproduct of system 1 typically contains about 3% by weight macrocyclicoligoester. The solution 190 enters system 2 as input solution 10. Theinput solution 10 is processed thorough system 2 to yield an outputproduct 130 substantially free from solvent.

FIG. 9 is a schematic flow diagram of an embodiment of a system forshaping macrocyclic oligoesters from a solution of macrocyclicoligoester and solvent According to this embodiment, the linked solventremoval systems 1 and 2, described above, are further linked to theprocess 5 for making pellets from a molten product illustrated in FIG.5. The input solution 110 is a dilute solution (e.g., about 1% by weightmacrocyclic oligoester) which is first processed though system 1 toyield a resulting output solution 190. The solution 190 that is theproduct of system 1 typically contains about 3% by weight macrocyclicoligoester. Solution 190 enters system 2 as input solution 10 and isprocessed thorough system 2 to yield an output product 130 substantiallyfree from solvent. The output product 130 may be molten. Output product130 enters process 5 as molten macrocyclic oligoester 530, which isprocessed through system 5 to yield pellet 435.

FIG. 10 is a schematic flow diagram of an embodiment of a system forshaping macrocyclic oligoesters from a solution of macrocyclicoligoester and solvent. According to this embodiment, the solventremoval system 2 is linked to the process 5, described above, which makepellets from a molten product. According to this embodiment, the inputsolution 10 containing about 3% by weight macrocyclic oligoester isprocessed thorough system 2 to yield an output product 130 substantiallyfree from solvent. In one embodiment, the output product 130 is molten.Output product 130 enters system 5 as molten macrocyclic oligoester 530,which is processed through system 5 to yield pellet 435.

Just as the processes in FIG. 8–10 can be linked to provide increasedbenefits, in other variations of such embodiments (not shown),alternative solvent removal system(s), for example, systems 1, 2, 3, and4, described above with reference to FIGS. 1–4, may be linked to oneanother and/or to processes for shaping macrocyclic oligoesters from asolution of macrocyclic oligoester and solvent, such as, for example,processes 5, 6, and 7, described above with reference to FIGS. 5–7. Forexample, referring again to FIG. 8, FIG. 9, and FIG. 10 the solventremoval system 2 can be replaced by system 3 (FIG. 3) or system 4 (FIG.4). Referring still to FIG. 9, and FIG. 10, the shaping process 5 can bereplaced by process 6 (FIG. 6).

The advantages of the above systems, processes and product prepregsinclude the ability to “drape” easily into a mold, the ability to flexwithout cracking and crumbling the resin drops, and the ability to useconventional pastillation equipment. Also, instead of placing thepellets on a conveyor belt, they are placed on a reinforcing fabric. Inaddition, the processes can be conducted isothermally (i.e. at constanttemperature) and in a vacuum bag or in a compression molding press.

Catalysts may be formulated with macrocyclic oligoesters to prepareprepregs. Catalysts may be part of a blend material of macrocyclicoligoesters, see U.S. Pat. No. 6,369,157, the entire contents of whichis incorporated by reference herein, or may be added before or duringthe formulation processes described herein. Catalysts that may beemployed in the invention include those that are capable of catalyzing atransesterification polymerization of a macrocyclic oligoester. As withstate-of-the-art processes for polymerizing macrocyclic oligoesters,organotin, and organotitanate compounds are the preferred catalysts,although other catalysts may be used. Detailed description ofpolymerization catalysts can be found in commonly assigned U.S. Ser. No.09/754,943 entitled “Macrocyclic Polyester Oligomers and Processes forPolymerizing the Same” by Winckler et al., U.S. Ser. No. 10/102,162entitled “Catalytic Systems” by Wang, and U.S. Ser. No. 10/040,530entitled “Polymer-Containing Organo-Metal Catalysts” by Wang, the entirecontents of which are incorporated by reference herein.

Illustrative examples of classes of tin compounds that may be used inthe invention includes monoalkyltin(IV) hydroxide oxides,monoalkyltin(IV) chloride dihydroxides, dialkyltin(IV) oxides,bistrialkyltin(IV) oxides, monoalkyltin(IV) trisalkoxides,dialkyltin(IV) dialkoxides, trialkyltin(IV) alkoxides, tin compoundshaving the formula (II):

and tin compounds having the formula (III):

wherein R₂ is a C₁₋₄ primary alkyl group, and R₃ is C₁₋₁₀ alkyl group.

Specific examples of organotin compounds that may be used in thisinvention include dibutyltin dioxide,1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-tetraoxacyclodecane,n-butyltin(IV) chloride dihydroxide, di-n-butyltin(IV) oxide, dibutyltindioxide, di-n-octyltin oxide, n-butyltin tri-n-butoxide,di-n-butyltin(IV) di-n-butoxide,2,2-di-n-butyl-2-stanna-1,3-dioxacycloheptane, and tributyltin ethoxide.See, e.g., U.S. Pat. No. 5,348,985 to Pearce et al. In addition, tincatalysts described in commonly owned U.S. Ser. No. 09/754,943(incorporated herein by reference in its entirety) may be used in thepolymerization reaction.

Titanate compounds that may be used in the invention include titanatecompounds described in commonly owned U.S. Ser. No. 09/754,943.Illustrative examples include tetraalkyl titanates (e.g.,tetra(2-ethylhexyl) titanate, tetraisopropyl titanate, and tetrabutyltitanate), isopropyl titanate, titanate tetraalkoxide. Otherillustrative examples include (a) titanate compounds having the formula(IV):

wherein each R₄ is independently an alkyl group, or the two R₄ groupstaken together form a divalent aliphatic hydrocarbon group; R₅ is aC₂₋₁₀ divalent or trivalent aliphatic hydrocarbon group; R₆ is amethylene or ethylene group; and n is 0 or 1,(b) titanate ester compounds having at least one moiety of the formula(V):

wherein each R₇ is independently a C₂₋₃ alkylene group; Z is O or N; R₈is a C₁₋₆ alkyl group or unsubstituted or substituted phenyl group;provided when Z is O, m=n=0, and when Z is N, m=0 or 1 and m+n=1, and(c) titanate ester compounds having at least one moiety of the formula(VI):

wherein each R₉ is independently a C₂₋₆ alkylene group; and q is 0 or 1.

The compositions and methods of the invention may be used to manufacturearticles of various size and shape from various macrocyclic oligoesters.Exemplary articles that may be manufactured by the invention includewithout limitation automotive body panels and chassis components, bumperbeams, aircraft wing skins, windmill blades, fluid storage tanks,tractor fenders, tennis rackets, golf shafts, windsurfing masts, toys,rods, tubes, bars stock, bicycle forks, and machine housings.

EXAMPLES

The following examples are provided to further illustrate and tofacilitate the understanding of the invention. These specific examplesare intended to be illustrative of the invention.

Example A

The macrocyclic oligoesters used in the following examples are themacrocyclic oligoesters of 1,4-butylene terephthalate. The macrocyclicoligoesters were prepared by heating a mixture of polyester linears,organic solvents, such as o-xylene and o-dichlorobenzene, which aresubstantially free from oxygen and water, and tin or titanium compoundsas transesterification catalysts. See U.S. Pat. No. 5,668,186(incorporated herein by reference in its entirety).

Example 1 Preparation of Macrocyclic (1,4-butylene terephthalate)Oligomer Pellets

Macrocyclic (1,4-butylene terephthalate) oligoester powder was fed at arate of about 9 kg/hr through an extruder at about 120° C. to melt intoa paste and processed at a rate of about 9 kg/hr through a Galaunderwater pelletizer available from Gala Industries (Eagle Rock, Va.).No die freeze off was observed. The material cut cleanly on the dieface. The pellets were strained out of the water and air dried tocontain 80 ppm or less of water.

Example 2 Macrocyclic (1,4-butylene terephthalate) Oligomer Pastilles

Macrocyclic (1,4-butylene terephthalate) oligomer powder containing lessthan 1,000 ppm solvent was melted in a tank at about 170° C. and fed ata rate of 60 kg/hr to a Sandvik Rotoformer to form pastilles. Nopartial-crystallization was used. The pastilles were amorphous andagglomerated together. The macrocyclic (1,4-butylene terephthalate)oligomer was pastilled smoothly into pastilles.

Example 3 Formulated Macrocyclic (1,4-butylene terephthalate) OligomerPastilles

Macrocyclic (1,4-butylene terephthalate) oligoester powder was meltedand melt blended at a temperature between about 120° C. and about 140°C. with additives including a polymerization catalyst (0.33% by weightFASTCAT 4101 (Atofina, Philadelphia, Pa.)) and thermal stabilizers (0.4%by Weight IRGANOX 1010 (Ciba Specialty Chemicals Corporation, Tarrytown,N.Y.)). The formulated product was then fed at a rate of about 45 kg/hrto the Sandvik Rotoformer to form pastilles, as in Example 2.

Example 4 Formulated Macrocyclic (1,4-butylene terephthalate) OligomerPastilles on Glass Mat

Macrocyclic (1,4-butylene terephthalate) oligoester powder was meltblended with catalyst (0.33% by weight FASTCAT 4101 catalyst) andstabilizers (0.4% by weight IRGANOX 1010) and pastilled onto glass matattached to the Sandvik Rotoformer belt. The Macrocyclic (1,4-butyleneterephthalate) oligoester contained less than 1000 ppm solvent. Theweight of macrocyclic (1,4-butylene terephthalate) oligoester depositedonto an area of glass mat was controlled to between about 400 g/m² toabout 800 g/m². The pastilles had a hemispherical shape and were about 7mm in diameter, the pastilles were spaced about 15 mm apart from oneanother. The glass mat prepreg was flexible, with good adhesion of themacrocyclic (1,4-butylene terephthalate) oligoester pastilles. Thisprepreg mat can be cured to crystallize the macrocyclic (1,4-butyleneterephthalate) oligoester to reduce moisture adsorption and tack. Theprepreg was polymerized at a temperature of about 190° C. to highmolecular weight polyester (about 80,000 Dalton).

Example 5 Solvent Removal via Stripping

A solution of macrocyclic (1,4-butylene terephthalate) oligoester ino-dichlorobenzene was fed to an Artisan evaporative stripper fromArtisan Industries, Inc. (Waltham, Mass.) A two-stage flash evaporatorwas operated at a temperature ranging between about 180° C. and about220° C. and at a pressure ranging between about 10 torr and aboutatmospheric pressure to concentrate a 10% solution of macrocyclic(1,4-butylene terephthalate) oligomer to less than 100 ppmo-dichlorobenzene.

Example 6 Solvent Removal via Evaporation and Stripping (ConstructiveExamnle)

An input solution of 3% by weight macrocyclic (1,4-butyleneterephthalate) oligoester in o-dichlorobenzene solution is fed at a rateof about 6,045 kg/hr into a series of rising film evaporators and afalling film stripper available from Artisan Industries, Inc. to producean output solution with solvent levels of less than 100 ppm at a rate ofabout 181 kg/hr.

In one embodiment, the input solution, having a temperature of about 65°C., is fed at a rate of about 6,045 kg/hr into a first rising filmevaporator having an evaporation surface area of about 317 ft². Thefirst rising film evaporator is held at temperature of about 180° C. atatmospheric pressure. Thereafter, the solution exits the first risingfilm evaporator and enters a first flash device. The first flash deviceis held at temperature of about 180° C. at atmospheric pressure. A firstcondenser captures the vaporized solvent that is removed in the firstrising film evaporator and the first flash device.

The solution exits the first flash device and travels at a temperatureof about 180° C. to a second rising film evaporator. The second risingfilm evaporator has an evaporation surface area of about 81 ft² and isheld at a temperature of about 193° C. at atmospheric pressure. Thesolution exiting the second rising film evaporator has a temperature ofabout 193° C. and enters a second flash device. The second flash deviceis held at a temperature of about 180° C. at atmospheric pressure. Asecond condenser captures the vaporized solvent that is removed in thesecond rising film evaporator and the second flash device.

The solution exits the second flash device and travels to a third risingfilm evaporator. The third rising film evaporator has an evaporationsurface area of about 21 ft² and is held at temperature of about 199° C.at atmospheric pressure. Thereafter, the solution exits the third risingfilm evaporator at a temperature of about 199° C. and enters a thirdflash device. The third flash device is held at a temperature of about180° C. at atmospheric pressure. A third condenser captures thevaporized solvent that is removed in the third rising film evaporatorand the third flash device.

The solution exits the third flash device and travels to a fourth risingfilm evaporator. The fourth rising film evaporator has an evaporationsurface area of about 8 ft² and is held at temperature of about 204° C.at atmospheric pressure. Thereafter, the solution exits the fourthrising film evaporator at a temperature of about 204° C. and enters afourth flash device. The fourth flash device is held at a temperature ofabout 180° C. at atmospheric pressure. A fourth condenser captures thevaporized solvent that is removed in the fourth rising film evaporatorand the fourth flash device. Each of the four condensers employ coolingwater to condense the vaporized solvent and bring the condensed solventto a temperature of about 176° C.

The solution exits the fourth flash device and travels to a fifth risingfilm evaporator. The fifth rising film evaporator has an evaporationsurface area of about 10 ft² and is held at temperature of about 226° C.at a pressure of about 1 torr. Thereafter, the solution exits the fifthrising film evaporator at a temperature of about 226° C. and enters thetop of a falling film stripper. The falling film stripper is held at atemperature of about 226° C. at a pressure of about 1 torr. A vacuumpump captures the vaporized solvent that is removed in the falling filmstripper and the fifth rising film evaporator. The vacuum pump is heldat about 0.5 torr. The vaporized solvent travels from the vacuum pump toa fifth condenser. The fifth condenser is sized at 75 ft² and employscooling water to condense the vaporized solvent and bring the condensedsolvent to a temperature of about 176° C.

Nitrogen from a nitrogen sparger is introduced to the solution travelingthrough the falling film stripper at a rate of about 9 kg/hr. Aftersparging, the macrocyclic oligoester product has a temperature of about226° C. and contains less than 100 ppm solvent. The macrocyclicoligoester exits the process at a rate of about 181 kg/hr.

Alternatively, a single flash device or a single condenser is employedin place of two or more of the flash devices and two or more of thecondensers that are described. A single flash device may be employed inthe place of the second, third, and fourth flash devices describedabove. A single flash device may house three distinct conduits for thesolutions exiting the second, third, and fourth rising film evaporators.Such a flash device may have three conduits that are adjacent to oneanother. The flash device may also be constructed so that the conduitfor the solution exiting the third rising film evaporator is placedinside the conduit for the solution exiting the second rising filmevaporator, and the conduit for the solution exiting the fourth risingfilm evaporator is placed inside the conduit for the solution exitingthe third rising film evaporator. A single condenser (e.g., a condenserwith a 500 ft² area) may be employed in the place of the second, third,and fourth condenser described above.

Each of the patent and patent application documents disclosedhereinabove are incorporated by reference herein in their entirety.

Variations, modifications, and other implementations of what isdescribed herein will occur to those of ordinary skill in the artwithout departing from the spirit and the scope of the invention asclaimed.

1. A process for isolating a macrocyclic oligoester, the processcomprising the steps of: (a) providing a solution comprising amacrocyclic oligoester and a solvent, the macrocyclic oligoestercomprising a structural repeat unit of formula (I):

wherein R is an alkylene, a cycloalkylene, or a mono- or polyoxyalkylenegroup and A is a divalent aromatic or alicyclic group; (b) removing thesolvent from the solution at an elevated temperature, at a reducedpressure, or both; and (c) collecting the macrocyclic oligoestersubstantially free from the solvent.
 2. The process of claim 1 whereinstep (b) comprises removing the solvent without using an anti-solvent.3. The process of claim 2 wherein step (b) comprises removing thesolvent at a temperature above 120° C.
 4. The process of claim 3 whereinstep (b) is conducted within a temperature range of about 180° C. toabout 200° C.
 5. The process of claim 2 wherein step (b) is conductedwithin a pressure range of about 0.001 torr to about 10 torr.
 6. Theprocess of claim 5 wherein step (b) is conducted within a pressure rangeof about 1 torr to about 100 torr.
 7. The process of claim 1 whereineach of step (b) and step (c) independently is continuous.
 8. Theprocess of claim 1 wherein step (b) is conducted with at least onesolvent removal apparatus selected from the group consisting of a risingfilm evaporator, a falling film stripper, a thin film evaporator, awiped film evaporator, a molecular still, a centrifuge, a filter, and ashort path evaporator.
 9. The process of claim 8 wherein the rising filmevaporator comprises a tubular heat exchanger.
 10. The process of claim8 wherein each solvent removal apparatus removes between about 80% andabout 90% of the solvent.
 11. The process of claim 1 wherein themacrocyclic oligoester comprises a macrocychc co-oligoester.
 12. Theprocess of claim 1 wherein the macrocyclic oligoester substantially freefrom the solvent contains less than about 200 ppm of the solvent. 13.The process of claim 1 wherein the macrocyclic oligoester substantiallyfree from the solvent contains less than about 10 ppm of the solvent.14. The process of claim 1 wherein the solution of a macrocyclicoligoester and a solvent comprises between about 1% and about 50% byweight of macrocyclic oligoester.
 15. The process of claim 1 wherein themacrocyclic oligoester comprises a structural repeat unit selected fromthe group consisting of ethylene terephthalate, propylene terephthalate,1,3-propylene terephthalate, 1 ,4-butylene terephthalate,1,4-cyclohexylenedimethylene terephthalate, and 1,2-ethylene 2,6-naphthalenedicarboxylate.
 16. The process of claim 1 wherein step (b)comprises removing the solvent at an elevated temperature and a reducedpressure using a first rising film evaporator; a second rising filmevaporator; and a falling film stripper.
 17. The process of claim 1wherein step (b) comprises removing the solvent at an elevatedtemperature and a reduced pressure using a first rising film evaporator;a first flash device; a first condenser; a second rising filmevaporator; a second flash device; a second condenser; a liquidreceiver; a sparger, and a falling film stripper.
 18. The process ofclaim 1 wherein step (b) comprises removing the solvent at an elevatedtemperature and a reduced pressure using a first short path evaporator;a second short path evaporator; and a falling film stripper.
 19. Theprocess of claim 1 wherein step (b) comprises removing the solvent at anelevated temperature and a reduced pressure using a first short pathevaporator; a first flash device; first condenser; a second short pathevaporator; a second flash device; a second condenser; a liquidreceiver; and a falling film stripper.
 20. The process of claim 1wherein step (b) comprises removing the solvent at a reduced pressure.21. The process of claim 20 wherein the reduced pressure is less thanabout 100 torr.
 22. The process of claim 20 wherein the reduced pressureis less than about 10 torr.
 23. The process of claim 20 wherein thereduced pressure is less than about 1 torr.
 24. The process of claim 20wherein the reduced pressure is less than about 0.1 torr.
 25. Theprocess of claim 1 wherein step (b) comprises removing the solvent at atemperature within a range from about 120° C. to about 280° C.
 26. Theprocess of claim 1 wherein step (b) comprises removing the solvent at atemperature within a range from about 120° C. to about 200° C.
 27. Theprocess of claim 1 wherein step (b) comprises removing the solvent at atemperature above about 180° C.
 28. The process of claim 1, wherein themacrocyclic oligoester is in a molten state when collected substantiallyfree from the solvent.
 29. The process of claim 1, wherein step (b)comprises removing the solvent at a temperature above a melting point ofthe macrocyclic oligoester.
 30. The process of claim 1 wherein themacrocyclic oligoester substantially free from the solvent contains lessthan about 50 ppm of the solvent.